Mark printing code as basic printing and/or print preview code.

chrome/browser/ui/webui/print_preview/print_preview_handler.cc

Index: chrome/browser/ui/webui/print_preview/print_preview_handler.cc
diff --git a/chrome/browser/ui/webui/print_preview/print_preview_handler.cc b/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
index 5af74615cd43c589b70dd0a8a8a2f518871f9b13..aa761e63b3446261c47d01e9050a673782492138 100644
--- a/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
+++ b/chrome/browser/ui/webui/print_preview/print_preview_handler.cc
@@ -291,7 +291,6 @@ void ReportPrintSettingsStats(const base::DictionaryValue& settings) {
                           &distill_page) && distill_page) {
     ReportPrintSettingHistogram(DISTILL_PAGE);
   }
-
 }
 
 // Callback that stores a PDF file on disk.
@@ -1004,6 +1003,7 @@ void PrintPreviewHandler::HandlePrint(const base::ListValue* args) {
     ReportUserActionHistogram(PRINT_WITH_CLOUD_PRINT);
     SendCloudPrintJob(data.get());
   } else {
+#if defined(ENABLE_BASIC_PRINTING)

[Vitaly Buka (NO REVIEWS), 2016/01/04 21:36:49]

As I remember basic printing is system dialog printing.
I made some efforts to enable (enable_basic_printing==0 and
enable_print_preview==1) builds.

Idea was to remove system dialog at all. 
But having that mobile platforms use that code, it's not going to happen.

So are you removing (enable_basic_printing==0 and enable_print_preview==1) case
intentionally?

[Lei Zhang, 2016/01/07 03:01:09]

We have:
no printing - embedded platforms?
enable_basic_printing only - Android
enable_print_preview only - ChromeOS
full printing - desktop

I'm getting rid of the defined(OS_CHROME) checks in this CL. In particular:

PrintWebViewHelper::PrintPagesNative() has a ChromeOS NOTREACHED(), and if you
follow the call stack for that, we should never get here on ChromeOS either.
ChromeOS should always have |is_cloud_printer| set to true. But rather than
marking this block as !OS_CHROME, I'm using the ENABLE_BASIC_PRINTING feature
flag.

[Vitaly Buka (NO REVIEWS), 2016/01/07 04:19:35]

It was possible to build on Windows (don't remember, but maybe on other desktops
too) with ENABLE_BASIC_PRINTING and with no PRINT_PREVIEW, using gyp defines.

This is not enabled on any build bots, so that config is probably degraded.
There was attempt to get closer to removing ENABLE_BASIC_PRINTING from desktops
at all and keep print preview only.

[Vitaly Buka (NO REVIEWS), 2016/01/07 04:21:14]

Sorry, I tried to say:
it was possible to build "without ENABLE_BASIC_PRINTING and with PRINT_PREVIEW"

[Lei Zhang, 2016/01/07 04:47:50]

With this CL, all the configurations are buildable except for "no printing".
There's no bots to test, and I'm fine with that. I just want to have better
separation, so if we shuffle the code around in the future, it's easier to
identify what goes where.

[Vitaly Buka (NO REVIEWS), 2016/01/07 23:50:23]

Then I am fine with that too :-)

     bool system_dialog = false;
     settings->GetBoolean(printing::kSettingShowSystemDialog, &system_dialog);
     if (system_dialog) {
@@ -1054,6 +1054,9 @@ void PrintPreviewHandler::HandlePrint(const base::ListValue* args) {
           printing::PrintViewManager::FromWebContents(initiator);
       print_view_manager->PrintPreviewDone();
     }
+#else
+    NOTREACHED();
+#endif   // defined(ENABLE_BASIC_PRINTING)
   }
 }